Modem Collection

From: William Donzelli <>
Date: Fri Jul 11 13:39:35 1997

> Just curious (again!) if anyone is collecting the early modems used on
> computers and what might have been the earliest commercial phone modem.
> I have several devices that are called modem eliminators and I believe
> these are basically serial cable boosters to increase the permissible
> cable length. My guess is that the earliest modems were accousticle
> (sp?) modems where the coupling was where the phone was laid onto the
> modem rather than a direct connect to the computer. Was there anything
> earlier or other type of device?

The earliest modems were actually for radio work, and started sometime in
the 1930's. By the end of World War Two, FSK radio modems were used with
radioteletype by the government. I have the receiver half of an early FSK
modem, called model FRA by the U.S.Navy. Made by RCA, it is probably
heavier than just about any home computer ever made (Of course the actual
radio transmitter tips the scale at 1100 pounds). The transmitter half of
the FSK set is just about as big, yet still eludes me.

Later, both Teletype and Kleinschmidt teleprinters could be fitted with
modems, either for radio or telephone use. The first ones are still
fairly huge, but use transistors. Western Union was an early user of
telephone modems, for use with type 33 teleprinters.

William Donzelli
Received on Fri Jul 11 1997 - 13:39:35 BST

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